Drum-style brake systems are well known in the prior art. The brake system is operated by hydraulic pressure which forces hydraulic pistons located in a wheel cylinder to extend away from the cylinder body in opposite directions. Each piston is connected to a respective brake shoe having brake lining material which faces the interior circumferential surface of the drum. As the pistons are forced outward, the shoes are displaced outward into frictional contact with the brake drum. An arrangement of springs are utilized to return the shoes to their original position once the hydraulic pressure exerted upon the wheel cylinder is released. Some brake systems have further utilized spring tension principles to "self-adjust" or cause the shoes and lining material to be set in place in a closer spacial relationship to the drum surface.
Over time, wheel cylinders begin to leak hydraulic brake fluid from normal wear. Typically, when changing a hydraulic wheel cylinder, a mechanic will remove the brake shoes, springs and all associated hardware, even in cases where the brake linings were not in need of replacement. The job entailed additional labor to remove the associated components and hardware instead of simply replacing the failed part.